A technique is known of searching ships which travel on very wide ocean from above by using various sensors installed in an artificial satellite or an aircraft as a search vehicle.
However, when the ground and ocean should be searched from the artificial satellite, the artificial satellite needs be arranged at so-called low orbit in hundreds kilometer from the ground in order to secure the resolution of the imaging sufficiently. In the artificial satellite which orbits the earth on such a low orbit, there is a limit in a time zone of staying above an area of a search object, unlike a case of the stationary satellite arranged at so-called geostationary orbit in about 36,000 kilometers from the ground.
Also, the regular replenishment of fuel is indispensable for the aircraft and there is a limit in the time of staying above the area of the search object. That is, the aircraft needs to repeat a routine of taking off from an airport or a base, flying to the area of the search object, carrying out a search operation, returning to the airport or the base, and then receiving various types of replenishment.
Moreover, an infrared sensor as an imaging unit used for a search vehicle cannot sometimes show the performance sufficiently in bad weather such as rain, and the imaging using a visible ray is unsuitable in night.
In addition to such a technical limitation, there is a limitation in the search vehicle usable in the actual search activity. That is, it is necessary to plan more effective search activity, in consideration of a limitation of the airport facilities near sufficiently from a predicted position of the target as the search object, a limitation of the search vehicles to be stood-by in the above airport facilities, and a limitation on the search vehicles actually usable in the range of the above limitations.
In conjunction with the above, Patent Literature 1 (JP H04-204187A) discloses an infrared-ray front monitoring apparatus. The infrared-ray front monitoring apparatus includes an infrared sensor, an image preprocessing section, a movement detecting section, a display section, a search schedule determining section, a sensor driving section and an operation section. Here, the infrared sensor images an infrared image. The image preprocessing section converts an image analog signal which is obtained from the infrared sensor into a digital signal. The movement detecting section detects a relative movement of an object in the image obtained from the image preprocessing section. The display section displays a position and a movement vector of the object obtained from the movement detecting section. The search schedule determining section generates a search pattern according to a relative movement quantity obtained from the movement detecting section. The sensor driving section turns the infrared sensor according to a visual axis drive angle which is instructed from the search schedule determining section. The operation section instructs the start-up and end of an automatic search mode.
Also, Patent Literature 2 (JP 2010-132073A) discloses a search work support system. This search work support system includes a navigation system, a radio receiver-transmitter, a database and an information processing unit. Here, in the navigation system, each of a plurality of rotorcrafts which carry out the search work measures a position and a speed of itself. The radio receiver-transmitter transmits and receives execution information of the search work by a radio signal to or from the other rotorcrafts. The database stores a search plan which contains position information of each of search areas of the rotorcrafts and the execution information of the search work of itself based on the search plan. The information processing unit plans a new search plan of itself based on the position and speed of itself measured by the navigation system, the execution information of the search work of the other rotor crafts received by the radio receiver-transmitter, and the search plan of the other rotor crafts stored in the database.